Devices for folding sheets are generally known. For example, U.S. Pat. No. 3,516,655 issued to Schmeck, U.S. Pat. No. 3,510,122 issued to Gavaghan, and U.S. Pat. No. 3,416,785 issued to Sherman all show devices for folding sheets, which include feeding rollers for feeding a sheet, a buckle chute for receiving the sheet and causing it to buckle, and folding rollers for grasping the buckled portion of the sheet in the nip thereof and creasing the buckled portion of the sheet to fold it as the sheet is pulled through. A second buckle chute can be disposed after the folding rollers for receiving the folded edge of the sheet, buckling the remaining portion of the sheet, and folding it by further rollers to form a second fold. Generally, there is an adjustable stop in each buckle chute, which is positioned to accommodate a desired location of the corresponding fold on the sheet. For certain folding applications the location of the fold is significant. For example, a typical billing statement is a form sheet which includes a return portion that can be separated from the remaining portion of the statement by a perforated line extending across the sheet. Preferably, one of the folds will be exactly on the perforated line, thus facilitating tearing of the return portion from the remaining portion of the statement. It has been a common problem that buckle chute folders form folds in the billing statement that are adjacent to the perforated lines of such statements. When the fold is off the perforated line, it is difficult to obtain a clean tear of the return portion from the remaining portion of the billing statement.
It is an object of the present invention to improve the reliability of buckle chute folders to fold on the perforated lines of the billing statements.